"My husband and I were so closely united by our affection and our common work that we were not afraid of anything, even of the difficulties of a material existence."

"I have always believed that science has the power to change the world for the better. I have always believed that science has the power to improve the lives of all people. And I am proud of it."

"One never notices what has been done; one can only see what remains to be done."

"There are sadistic scientists who hurry to hunt down errors instead of establishing the truth."

"A scientist must be a child. He must be curious. He must be eager to learn. He must be willing to make mistakes."